1. Field of the Invention
This invention relates to a camera having incorporated therein a sound producing device for performing various kinds of displays or indications by means of producing sounds.
2. Description of the Prior Art
In conventional cameras, the various kinds of warning displays or indications are visually performed by using a meter needle or light-emitting element positioned within the view finder of the camera. Such visual display method, though being effective for the display of various kinds of warnings for the camera, is not always convenient for the operator whose concentration is directed toward catching an image of a scene to be photographed in the finder and is trying to properly frame the subject. In this situation, he is apt to overlook other things such as a warning display in the finder. Accordingly, many examples of exposure failures will result. For minimizing such failures, various means such as creating an energized display to intermittently flash on and off was utilized, but a warning using only the visual sense is simply not sufficient. For this purpose, it is proposed to employ a warning by the auditory sense in addition thereto. A system for performing the various warning displays in the simple intermittent sound or continuous sound form by a sound producing device (speaker) of extremely thin thickness incorporated in the camera was the basis of a U.S. patent application filed on Aug. 21, 1978 and given Ser. No. 934,723, now abandoned.
In the invention of the above mentioned patent application, the sound from the speaker incorporated within the camera is an intermittent sound or continuous sound of a single frequency. By this sound, it is made possible for the operator who would be otherwise unaware of the visual warning display as he is engaged in aligning the camera with the scene to be photographed to avoid exposure failure, since there is little possibility of missing the sound from the speaker incorporated in the camera when such warning sound arises in the neighbourhood of the operator's ear. However, the warning sound in the invention of the above mentioned patent application is a simple intermittent sound or continuous sound, so that it is difficult to distinctly display different warnings by such sound. Even when the frequency was increased and the intermittency also increased, it was difficult to intuitively discriminate this and to recognize which warning is displayed.